There are various types of water dispensers disclosed in the prior art, however many of these dispensers are complex in design and costly in manufacturing. Specifically many of these dispensers address the ability to have a reservoir of water that dispenses hot water on command, as opposed to our invention which provides hot water on demand. Many of these dispensers maintain the water at a constant pre-determined temperature by having a sensor set to the pre-determined temperature which engages a heating unit when the temperature drops below the pre-determined temperature.
Conventional heating systems are utilized in all water dispensing applications that are currently available in the retail market. Conventional heating systems utilize a variety of approaches, including immersion style and banded heating elements, which are all based on resistance style heating mechanisms. Temperature is controlled either electronically or through the use of mechanical thermostats, and regulates the temperature of the water between a low and upper set-point as defined by the control mechanism utilized. These heating systems operate at all times, e.g., 24 hours a day, 7 days a week, continuously, retaining the fluid within the hot tank system within the pre-determined control levels. Continuous operation of heating systems is known to be very inefficient with respect to energy consumption, and leads to significant performance issues, reducing component longevity.
Prior art combination water dispensers have been devised to address these issues. For example, U.S. Pat. No. 5,019,690 issued on May 28, 1991 to Knepler discloses a boiling water, dispenser includes a hot water reservoir, a user-actuated faucet for drawing boiling water from a discharge zone at the top of the reservoir, and a solenoid-actuated valve for admitting unheated water to an inlet zone at the bottom of the reservoir. An electric resistance heating element within the reservoir is supplied with AC current through a series-connected bilateral switch device which is periodically switched on and off in response to the sensing of steam in a reservoir venting conduit to maintain the dispensing temperature at the boiling point.
U.S. Pat. No. 5,038,752 issued to Anson on Aug. 13, 1991 discloses a sensor assembly for a boiling water dispenser that includes clamping members for mounting a sensor such as a thermister in position to sense the presence and absence of steam. The activation of this sensor is based upon steam generation, which requires water temperatures in excess of 100° C. (212° F.).
U.S. Pat. No. 4,871,089 issued to Rader et al. on Oct. 3, 1989 and relates to a hot water dispenser is provided for dispensing a selected volume of water at a predetermined water temperature. The dispenser has a body defining a pre-determined sized cavity having an inlet for receiving cold water and an outlet for dispensing hot water. A heating mechanism is disposed within the body for heating the water contained within the cavity. A manually operable timer switch is operated to energize the heating mechanism and to select a time period for maintaining the heating mechanism energized. This selected time period determines the selected volume of heated water dispensed. A thermally responsive mechanism enables dispensing water from the outlet responsive to the predetermined water temperature of the heated water.
Knepler is the owner of U.S. Pat. No. 4,978,833 which issued on Dec. 18, 1990 and discloses a hot water dispenser includes a hot water reservoir, a user-actuated faucet for drawing hot water from an outlet zone near the top of the reservoir, and a solenoid-actuated valve for admitting unheated water to an inlet zone at the bottom of the reservoir. An inline flow regulator establishes an inlet flow rate less than the faucet flow rate to maximize the volume of hot water available at the faucet. An electric resistance heating element within the reservoir is supplied with AC current through a series-connected bilateral switch device which is periodically switched on and off in accordance with the temperature of water sensed by a sensor at the faucet to maintain a constant dispensing temperature. The switch device is thermally coupled to the bottom of the reservoir such that the reservoir acts as a heat sink to dissipate heat generated during switching. An indicator lamp conditioned by the sensor confirms to the user that the dispensing temperature is within a predetermined range.
Forsberg is the owner of U.S. Pat. No. 6,182,453 which issued on Feb. 6, 2001, and describes a portable water generating system for production of high-purity liquid water by condensation of dew from ambient air. Forsberg describes a heated, food type, stainless steel tank with an insulating jacket, being in fluid communication with the heated fluid delivery control valve and the ambient temperature water in the storage tank. Water at a temperature of up to about 75° C. (167° F.) can be delivered from the heated fluid delivery control valve. Forsberg additionally describes an alternate method of supplying heated water through a resistance heated tube of sufficient length to heat water being delivered from the ambient temperature zone of the reservoir to the hot water external valve.
Thus a water dispenser having a superior energy efficient, -user activated hot water on demand mechanism, with a single dispensing mechanism for both room temperature water and hot water where the hot water is generated by a user activated on demand heating mechanism is desirable.